[PATCH] swsusp: Do not fail if resume device is not set
[linux-2.6.git] / kernel / power / user.c
1 /*
2  * linux/kernel/power/user.c
3  *
4  * This file provides the user space interface for software suspend/resume.
5  *
6  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
7  *
8  * This file is released under the GPLv2.
9  *
10  */
11
12 #include <linux/suspend.h>
13 #include <linux/syscalls.h>
14 #include <linux/reboot.h>
15 #include <linux/string.h>
16 #include <linux/device.h>
17 #include <linux/miscdevice.h>
18 #include <linux/mm.h>
19 #include <linux/swap.h>
20 #include <linux/swapops.h>
21 #include <linux/pm.h>
22 #include <linux/fs.h>
23 #include <linux/console.h>
24 #include <linux/cpu.h>
25 #include <linux/freezer.h>
26
27 #include <asm/uaccess.h>
28
29 #include "power.h"
30
31 #define SNAPSHOT_MINOR  231
32
33 static struct snapshot_data {
34         struct snapshot_handle handle;
35         int swap;
36         struct bitmap_page *bitmap;
37         int mode;
38         char frozen;
39         char ready;
40 } snapshot_state;
41
42 static atomic_t device_available = ATOMIC_INIT(1);
43
44 static int snapshot_open(struct inode *inode, struct file *filp)
45 {
46         struct snapshot_data *data;
47
48         if (!atomic_add_unless(&device_available, -1, 0))
49                 return -EBUSY;
50
51         if ((filp->f_flags & O_ACCMODE) == O_RDWR)
52                 return -ENOSYS;
53
54         nonseekable_open(inode, filp);
55         data = &snapshot_state;
56         filp->private_data = data;
57         memset(&data->handle, 0, sizeof(struct snapshot_handle));
58         if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
59                 data->swap = swsusp_resume_device ?
60                         swap_type_of(swsusp_resume_device, 0, NULL) : -1;
61                 data->mode = O_RDONLY;
62         } else {
63                 data->swap = -1;
64                 data->mode = O_WRONLY;
65         }
66         data->bitmap = NULL;
67         data->frozen = 0;
68         data->ready = 0;
69
70         return 0;
71 }
72
73 static int snapshot_release(struct inode *inode, struct file *filp)
74 {
75         struct snapshot_data *data;
76
77         swsusp_free();
78         data = filp->private_data;
79         free_all_swap_pages(data->swap, data->bitmap);
80         free_bitmap(data->bitmap);
81         if (data->frozen) {
82                 mutex_lock(&pm_mutex);
83                 thaw_processes();
84                 enable_nonboot_cpus();
85                 mutex_unlock(&pm_mutex);
86         }
87         atomic_inc(&device_available);
88         return 0;
89 }
90
91 static ssize_t snapshot_read(struct file *filp, char __user *buf,
92                              size_t count, loff_t *offp)
93 {
94         struct snapshot_data *data;
95         ssize_t res;
96
97         data = filp->private_data;
98         res = snapshot_read_next(&data->handle, count);
99         if (res > 0) {
100                 if (copy_to_user(buf, data_of(data->handle), res))
101                         res = -EFAULT;
102                 else
103                         *offp = data->handle.offset;
104         }
105         return res;
106 }
107
108 static ssize_t snapshot_write(struct file *filp, const char __user *buf,
109                               size_t count, loff_t *offp)
110 {
111         struct snapshot_data *data;
112         ssize_t res;
113
114         data = filp->private_data;
115         res = snapshot_write_next(&data->handle, count);
116         if (res > 0) {
117                 if (copy_from_user(data_of(data->handle), buf, res))
118                         res = -EFAULT;
119                 else
120                         *offp = data->handle.offset;
121         }
122         return res;
123 }
124
125 static int snapshot_ioctl(struct inode *inode, struct file *filp,
126                           unsigned int cmd, unsigned long arg)
127 {
128         int error = 0;
129         struct snapshot_data *data;
130         loff_t avail;
131         sector_t offset;
132
133         if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
134                 return -ENOTTY;
135         if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
136                 return -ENOTTY;
137         if (!capable(CAP_SYS_ADMIN))
138                 return -EPERM;
139
140         data = filp->private_data;
141
142         switch (cmd) {
143
144         case SNAPSHOT_FREEZE:
145                 if (data->frozen)
146                         break;
147                 mutex_lock(&pm_mutex);
148                 error = disable_nonboot_cpus();
149                 if (!error) {
150                         error = freeze_processes();
151                         if (error) {
152                                 thaw_processes();
153                                 enable_nonboot_cpus();
154                                 error = -EBUSY;
155                         }
156                 }
157                 mutex_unlock(&pm_mutex);
158                 if (!error)
159                         data->frozen = 1;
160                 break;
161
162         case SNAPSHOT_UNFREEZE:
163                 if (!data->frozen)
164                         break;
165                 mutex_lock(&pm_mutex);
166                 thaw_processes();
167                 enable_nonboot_cpus();
168                 mutex_unlock(&pm_mutex);
169                 data->frozen = 0;
170                 break;
171
172         case SNAPSHOT_ATOMIC_SNAPSHOT:
173                 if (data->mode != O_RDONLY || !data->frozen  || data->ready) {
174                         error = -EPERM;
175                         break;
176                 }
177                 mutex_lock(&pm_mutex);
178                 /* Free memory before shutting down devices. */
179                 error = swsusp_shrink_memory();
180                 if (!error) {
181                         suspend_console();
182                         error = device_suspend(PMSG_FREEZE);
183                         if (!error) {
184                                 in_suspend = 1;
185                                 error = swsusp_suspend();
186                                 device_resume();
187                         }
188                         resume_console();
189                 }
190                 mutex_unlock(&pm_mutex);
191                 if (!error)
192                         error = put_user(in_suspend, (unsigned int __user *)arg);
193                 if (!error)
194                         data->ready = 1;
195                 break;
196
197         case SNAPSHOT_ATOMIC_RESTORE:
198                 snapshot_write_finalize(&data->handle);
199                 if (data->mode != O_WRONLY || !data->frozen ||
200                     !snapshot_image_loaded(&data->handle)) {
201                         error = -EPERM;
202                         break;
203                 }
204                 mutex_lock(&pm_mutex);
205                 pm_prepare_console();
206                 suspend_console();
207                 error = device_suspend(PMSG_PRETHAW);
208                 if (!error) {
209                         error = swsusp_resume();
210                         device_resume();
211                 }
212                 resume_console();
213                 pm_restore_console();
214                 mutex_unlock(&pm_mutex);
215                 break;
216
217         case SNAPSHOT_FREE:
218                 swsusp_free();
219                 memset(&data->handle, 0, sizeof(struct snapshot_handle));
220                 data->ready = 0;
221                 break;
222
223         case SNAPSHOT_SET_IMAGE_SIZE:
224                 image_size = arg;
225                 break;
226
227         case SNAPSHOT_AVAIL_SWAP:
228                 avail = count_swap_pages(data->swap, 1);
229                 avail <<= PAGE_SHIFT;
230                 error = put_user(avail, (loff_t __user *)arg);
231                 break;
232
233         case SNAPSHOT_GET_SWAP_PAGE:
234                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
235                         error = -ENODEV;
236                         break;
237                 }
238                 if (!data->bitmap) {
239                         data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0));
240                         if (!data->bitmap) {
241                                 error = -ENOMEM;
242                                 break;
243                         }
244                 }
245                 offset = alloc_swapdev_block(data->swap, data->bitmap);
246                 if (offset) {
247                         offset <<= PAGE_SHIFT;
248                         error = put_user(offset, (sector_t __user *)arg);
249                 } else {
250                         error = -ENOSPC;
251                 }
252                 break;
253
254         case SNAPSHOT_FREE_SWAP_PAGES:
255                 if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
256                         error = -ENODEV;
257                         break;
258                 }
259                 free_all_swap_pages(data->swap, data->bitmap);
260                 free_bitmap(data->bitmap);
261                 data->bitmap = NULL;
262                 break;
263
264         case SNAPSHOT_SET_SWAP_FILE:
265                 if (!data->bitmap) {
266                         /*
267                          * User space encodes device types as two-byte values,
268                          * so we need to recode them
269                          */
270                         if (old_decode_dev(arg)) {
271                                 data->swap = swap_type_of(old_decode_dev(arg),
272                                                         0, NULL);
273                                 if (data->swap < 0)
274                                         error = -ENODEV;
275                         } else {
276                                 data->swap = -1;
277                                 error = -EINVAL;
278                         }
279                 } else {
280                         error = -EPERM;
281                 }
282                 break;
283
284         case SNAPSHOT_S2RAM:
285                 if (!data->frozen) {
286                         error = -EPERM;
287                         break;
288                 }
289
290                 if (!mutex_trylock(&pm_mutex)) {
291                         error = -EBUSY;
292                         break;
293                 }
294
295                 if (pm_ops->prepare) {
296                         error = pm_ops->prepare(PM_SUSPEND_MEM);
297                         if (error)
298                                 goto OutS3;
299                 }
300
301                 /* Put devices to sleep */
302                 suspend_console();
303                 error = device_suspend(PMSG_SUSPEND);
304                 if (error) {
305                         printk(KERN_ERR "Failed to suspend some devices.\n");
306                 } else {
307                         /* Enter S3, system is already frozen */
308                         suspend_enter(PM_SUSPEND_MEM);
309
310                         /* Wake up devices */
311                         device_resume();
312                 }
313                 resume_console();
314                 if (pm_ops->finish)
315                         pm_ops->finish(PM_SUSPEND_MEM);
316
317  OutS3:
318                 mutex_unlock(&pm_mutex);
319                 break;
320
321         case SNAPSHOT_PMOPS:
322                 switch (arg) {
323
324                 case PMOPS_PREPARE:
325                         if (pm_ops->prepare) {
326                                 error = pm_ops->prepare(PM_SUSPEND_DISK);
327                         }
328                         break;
329
330                 case PMOPS_ENTER:
331                         kernel_shutdown_prepare(SYSTEM_SUSPEND_DISK);
332                         error = pm_ops->enter(PM_SUSPEND_DISK);
333                         break;
334
335                 case PMOPS_FINISH:
336                         if (pm_ops && pm_ops->finish) {
337                                 pm_ops->finish(PM_SUSPEND_DISK);
338                         }
339                         break;
340
341                 default:
342                         printk(KERN_ERR "SNAPSHOT_PMOPS: invalid argument %ld\n", arg);
343                         error = -EINVAL;
344
345                 }
346                 break;
347
348         case SNAPSHOT_SET_SWAP_AREA:
349                 if (data->bitmap) {
350                         error = -EPERM;
351                 } else {
352                         struct resume_swap_area swap_area;
353                         dev_t swdev;
354
355                         error = copy_from_user(&swap_area, (void __user *)arg,
356                                         sizeof(struct resume_swap_area));
357                         if (error) {
358                                 error = -EFAULT;
359                                 break;
360                         }
361
362                         /*
363                          * User space encodes device types as two-byte values,
364                          * so we need to recode them
365                          */
366                         swdev = old_decode_dev(swap_area.dev);
367                         if (swdev) {
368                                 offset = swap_area.offset;
369                                 data->swap = swap_type_of(swdev, offset, NULL);
370                                 if (data->swap < 0)
371                                         error = -ENODEV;
372                         } else {
373                                 data->swap = -1;
374                                 error = -EINVAL;
375                         }
376                 }
377                 break;
378
379         default:
380                 error = -ENOTTY;
381
382         }
383
384         return error;
385 }
386
387 static const struct file_operations snapshot_fops = {
388         .open = snapshot_open,
389         .release = snapshot_release,
390         .read = snapshot_read,
391         .write = snapshot_write,
392         .llseek = no_llseek,
393         .ioctl = snapshot_ioctl,
394 };
395
396 static struct miscdevice snapshot_device = {
397         .minor = SNAPSHOT_MINOR,
398         .name = "snapshot",
399         .fops = &snapshot_fops,
400 };
401
402 static int __init snapshot_device_init(void)
403 {
404         return misc_register(&snapshot_device);
405 };
406
407 device_initcall(snapshot_device_init);